Nadia has walked her dog for a total of $45$ kilometers since she started walking daily. She has been walking $9$ kilometers each day. For how many days has Nadia been walking?
Explanation: The number of days that Nadia has been walking is the total number of kilometers walked divided by the number of kilometers walked each day. $45\text{ kilometers} \div 9\text{ kilometers per day} = \text{number of days walking}$ $45\text{ kilometers} \div 9\text{ kilometers per day} = 5\text{ days}$